A builder is generally defined as a substance which has an effect of increasing the surface activity of a surfactant and enhancing its powder characteristics when mixed with the surfactant, and is required to be excellent in such properties as washing power, chelating effect, dispersibility, emulsifying effect, stability to hard water, anti-corrosive effect and economical factor and devoid of any cause to environmental pollution. Examples of builders known from the past include various phosphates besides sodium tripolyphosphate, sodium metasilicate, Glauber's salt and sodium carbonate. However, none of them satisfies all of the requisites above mentioned. Accordingly, it can hardly be said that a builder which is fully satisfactory for practical purposes has been developed. For example, the use of phosphates involves a problem in disposal of waste water, while a common type of silicate has a poor stability to hard water and Glauber's salt is inferior, although it is cheap, in the inherent performance as builder. Among them, the phosphates are used widely for practical purposes by virtue of their excellent inherent performance as builder, such as higher washing power. However, the use of the phosphates involves problems in disposal of waste water and of toxicity. In the field of detergents, therefore, there is a great demand for developing a builder which is excellent in the inherent performance as builder and involves no problem in disposal of waste water and in toxicity.